are you waiting for my new video dropping soon on revdex? 📚
this time i’m going to share an advanced android shared library modification technique. here’s a small hint about what the upcoming video will cover we’ll start by showing how to properly expand an elf shared library, how to inject your own compiled assembly code into the binary, how to create a new pht entry, connect it to a loadable segment, and build a valid memory mapping for that new region. from there, we’ll calculate the required file offsets, virtual addresses, segment sizes, alignment, and binary layout by hand, then inject the actual bytes directly into the library. we’ll also cover how to relocate and rebuild parts of the program header table when the original layout does not have enough space, how to move structures safely without causing overlap, how to expand the binary downward, and how to reallocate the full body while keeping the loader mapping consistent.
no scripting frameworks, no hook libraries, and no automated binary patching tools will be used for the core process. everything will be done through manual calculation and direct hex patching so you can understand what is actually happening inside the elf file instead of blindly relying on automation. we won’t just overwrite existing unused bytes. we’ll work with real binary expansion, insert new bytes, create new mapped regions, modify pht entries, and verify how those regions are represented in memory a lot of what i’ll show in this video comes from techniques we learned gradually through long-term practical experience, and the goal is to explain the process from the binary layout level rather than only showing the final patch
tools used
#1 ida pro
#2 hxd hex editor
this time i’m going to share an advanced android shared library modification technique. here’s a small hint about what the upcoming video will cover we’ll start by showing how to properly expand an elf shared library, how to inject your own compiled assembly code into the binary, how to create a new pht entry, connect it to a loadable segment, and build a valid memory mapping for that new region. from there, we’ll calculate the required file offsets, virtual addresses, segment sizes, alignment, and binary layout by hand, then inject the actual bytes directly into the library. we’ll also cover how to relocate and rebuild parts of the program header table when the original layout does not have enough space, how to move structures safely without causing overlap, how to expand the binary downward, and how to reallocate the full body while keeping the loader mapping consistent.
no scripting frameworks, no hook libraries, and no automated binary patching tools will be used for the core process. everything will be done through manual calculation and direct hex patching so you can understand what is actually happening inside the elf file instead of blindly relying on automation. we won’t just overwrite existing unused bytes. we’ll work with real binary expansion, insert new bytes, create new mapped regions, modify pht entries, and verify how those regions are represented in memory a lot of what i’ll show in this video comes from techniques we learned gradually through long-term practical experience, and the goal is to explain the process from the binary layout level rather than only showing the final patch
tools used
#1 ida pro
#2 hxd hex editor